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Protect Your Plants: A Beginner's Guide to Using Floating Row Cover

If you’ve never used a floating row cover, we suggest you run, don’t walk, to the nearest garden supply store, and pick up a roll today. It’s an inexpensive, versatile tool that, when used correctly, will give you decent chemical-free pest protection and a couple of extra weeks of growing time on both ends of the season.

No, it’s not magic, but it is a miracle worker in the garden. Frost in the forecast? Not a problem—just cover your tender seedlings with a layer of frost cloth. Bad year for cabbage loopers? No need to worry; just cover your cabbages with row cover to keep pests off your plants. 

It’s worth investing in row cover, and you can likely find it at your nearest garden supply store or even online. Row cover allows your plants a little bit of buffer against unpredictable weather and protection from pests, giving them the extra boost they need to perform at their best. It’s affordable and easy to use, so there’s no excuse not to try it out this year! 

Keep reading for a more detailed explanation of what row cover is, how it works, and how to use it for frost and pest protection in your garden.

What is floating row cover?

Who doesn’t love a comfortable blanket? The right blanket is soft and keeps you warm and cozy, no matter what the outside temps. Well, floating row cover is essentially a blanket for your garden—it keeps young seedlings warm and thriving, even when outside temperatures aren’t quite tolerable for young transplants yet.

Floating row cover is a lightweight, breathable fabric that is placed over your plants to provide protection from the elements and pests. The cover "floats" over the plants, giving them room to grow without being smothered.

Many know it by the brand name Reemay, but generic and brand-name row cover is made the same. The white fabric is woven polyester or polypropylene, and this permeable material allows water and light to pass through while providing a barrier against wind, cold air, and pests.

Also called frost cloth due to its primary purpose of insulating plants, row cover comes in several different weights—lightweight, medium weight, and heavyweight, and each type has a different purpose. Lightweight fabrics are more often used for pest control and to halt heat-sensitive herbs and greens from bolting, while heavyweight frost cloth is perfect for protecting plants from dips in temperature.

According to an article published by the University of New Hampshire, row cover can raise temperatures anywhere between 2℉ and 10℉ underneath it, depending on the material and its weight. The fabrics hold in heat as well as moisture, creating a perfect environment for young plants to grow rapidly.

Most growers use frost cloth for season extension since the fabric warms the soil and the plants underneath it by several degrees. An article published by the University of Wisconsin-Madison claims that row cover can “warm the local environment sufficiently to harvest certain crops a week or two early,” especially on a south-facing slope.

Plants that benefit from frost cloth

Many different types of plants benefit when grown under floating row cover, including leafy greens, brassicas, and root vegetables. Row cover is commonly used to protect cool-season crops from frost and pest damage, including:

Row cover is also an invaluable tool for warm-season crops like beans, cucumbers, tomatoes, and peppers. Since heavyweight frost cloth can add up to 10 degrees of warmth, cold-sensitive plants can be planted a week or two early and get a jumpstart on the season. 

While row cover can remain on root crops and leafy green vegetables all season long, you will have to remove the cloth from plants like cucumbers and beans that require pollination for fruit. This doesn’t mean that row cover isn’t helpful for these crops—in fact, row cover can work wonders for these crops in the beginning. But there will come a point when the row cover needs removing and won’t be an effective pest control mechanism or insulating barrier after that point.

In short, there’s no crop you can’t use row cover on, but there are some limitations to using row cover on certain crops.  

Pest control with floating row cover 

Frost cloth isn’t just used for season extension; it’s frequently used all summer long as a pest management tactic.

If you’ve struggled with a pest infestation, you know full well the struggle of keeping these pesky little invaders off of your precious plants. For this reason, many growers keep row cover on their crops year-round to manage pests without chemical sprays.

Not only does frost cloth add warmth, but even the most lightweight fabrics serve as an effective pest control mechanism when used correctly. The permeable design of row cover allows plants to absorb sunlight while preventing pests from passing through the fabric to the plants. Some of the pests that can be deterred with row cover include:

  • Caterpillars
  • Fleabeetles
  • Onion maggot
  • Seedcorn maggot
  • Cucumber beetles
  • Carrot flies
  • Cabbage moths
  • Leafhoppers
  • Thrips

No, it’s not a foolproof method, but it is chemical-free and less labor-intensive than other methods. For row cover to be a functional pest control method, there needs to be a tight seal between the ground and the row. This can be achieved by weighing down the row cover with rocks or sandbags and digging in the edge under a few inches of dirt.

There is one caveat to row cover as a pest control method—some pests emerge from the soil (including fleabeetle larvae and maggots), so row cover won’t help mulch if your plants are already in a heavily infested area.

How to set up floating row cover in 3 simple steps

Installing floating row cover is a straightforward process, and once you’ve done it a few times, it will become second nature. Frost cloth isn’t needed until after you’ve prepared your soil and planted your transplants, so make sure to do these tasks first. You can wait to put down row cover until there’s a frost in the forecast, or you can cover your plants from day one to aid in the hardening-off process.

One additional tip: while you can water plants through the fabric, it’s not a bad idea to weed the bed thoroughly and give the plants a good soak before you cover the bed with frost cloth—it just saves you the work of moving the row cover later on.

1. Install hoops every five feet

This is an optional step since you can drape row cover directly over plants. Draping does not add as much warmth as creating a low tunnel, but draping is just as effective for pest control.

To work properly for frost protection, the row cover needs to be floating—meaning the fabric needs to be elevated above the plants. Anywhere that a leaf comes into contact with the fabric runs the risk of frostbite, so you’ll want to create a bubble of insulation by suspending the fabric above plant tops. To achieve this, you can cover the length of the bed with hoops that can hold up the fabric.

You can buy wire or fiberglass hoops where you buy your floating row cover, or you can make your own by purchasing a row of nine-gauge wire and cutting it to size. How long you cut the wire depends on the purpose of the fabric—to cover seedlings on a chilly night, you can get away with three-foot-long hoops. To protect mature plants from pests, cut pieces of wire at least four or five feet in length. You may need to readjust the hoops as plants grow, making them narrower and taller to accommodate bigger plants. 

2. Pull the row cover over the hoops

Recruit a friend to help you with this step and save yourself some frustration! Have your partner hold the fabric at one end of the bed and walk to the other end of the bed, pulling the fabric over the hoops as you go.

If you’re not using hoops, drape the row cover directly over the seedlings. Make sure that the fabric covers the whole row (width as well as length), and adjust the fabric if needed

3. Pin the fabric down

Weighing down row cover is twofold: it keeps the fabric from blowing away in the wind and creates a barrier between pests and the plants. You’ll want to add weights every five feet or so, and rocks, cinderblocks, bricks, sandbags, and even t-posts do the job well. 

While you need to secure both sides of the row cover, designate one side as a permanent ‘hinge’ that allows you to pull the fabric to one side to access the plants underneath. Alternatively, you can use a shovel to scoop dirt onto the fabric and weigh the edges down.

If you live in an area with windy conditions, you may want to secure the cover further using stakes or pins.

Floating row cover is one of the best tools for season extension and pest control since it is inexpensive, accessible, and easy to use. Use row cover to protect your garden from freezing temperatures in the spring and fall or as a form of chemical-free pest management in the summer.

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